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Add ModelContextProtocol.AspNetCore (#160)
* Add ModelContextProtocol.AspNetCore - Remove IServerTransport and HttpListenerSseServerTransport - Replace HttpListenerSseServerTransport usage in tests with ASP.NET Core. Co-authored-by: Eirik Tsarpalis <[email protected]> Co-authored-by: Jeff Handley <[email protected]>
1 parent 330e526 commit 973c7c0

30 files changed

+332
-831
lines changed

Diff for: ‎ModelContextProtocol.sln

+7
Original file line numberDiff line numberDiff line change
@@ -50,6 +50,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "QuickstartWeatherServer", "
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EndProject
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Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "QuickstartClient", "samples\QuickstartClient\QuickstartClient.csproj", "{0D1552DC-E6ED-4AAC-5562-12F8352F46AA}"
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EndProject
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Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ModelContextProtocol.AspNetCore", "src\ModelContextProtocol.AspNetCore\ModelContextProtocol.AspNetCore.csproj", "{37B6A5E0-9995-497D-8B43-3BC6870CC716}"
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EndProject
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Global
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GlobalSection(SolutionConfigurationPlatforms) = preSolution
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Debug|Any CPU = Debug|Any CPU
@@ -92,6 +94,10 @@ Global
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{0D1552DC-E6ED-4AAC-5562-12F8352F46AA}.Debug|Any CPU.Build.0 = Debug|Any CPU
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{0D1552DC-E6ED-4AAC-5562-12F8352F46AA}.Release|Any CPU.ActiveCfg = Release|Any CPU
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{0D1552DC-E6ED-4AAC-5562-12F8352F46AA}.Release|Any CPU.Build.0 = Release|Any CPU
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{37B6A5E0-9995-497D-8B43-3BC6870CC716}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
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{37B6A5E0-9995-497D-8B43-3BC6870CC716}.Debug|Any CPU.Build.0 = Debug|Any CPU
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{37B6A5E0-9995-497D-8B43-3BC6870CC716}.Release|Any CPU.ActiveCfg = Release|Any CPU
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{37B6A5E0-9995-497D-8B43-3BC6870CC716}.Release|Any CPU.Build.0 = Release|Any CPU
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EndGlobalSection
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GlobalSection(SolutionProperties) = preSolution
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HideSolutionNode = FALSE
@@ -107,6 +113,7 @@ Global
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{0C6D0512-D26D-63D3-5019-C5F7A657B28C} = {02EA681E-C7D8-13C7-8484-4AC65E1B71E8}
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{4653EB0C-8FC0-98F4-E9C8-220EDA7A69DF} = {02EA681E-C7D8-13C7-8484-4AC65E1B71E8}
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{0D1552DC-E6ED-4AAC-5562-12F8352F46AA} = {02EA681E-C7D8-13C7-8484-4AC65E1B71E8}
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{37B6A5E0-9995-497D-8B43-3BC6870CC716} = {A2F1F52A-9107-4BF8-8C3F-2F6670E7D0AD}
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EndGlobalSection
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GlobalSection(ExtensibilityGlobals) = postSolution
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SolutionGuid = {384A3888-751F-4D75-9AE5-587330582D89}

Diff for: ‎samples/AspNetCoreSseServer/AspNetCoreSseServer.csproj

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@@ -8,6 +8,7 @@
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<ItemGroup>
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<ProjectReference Include="..\..\src\ModelContextProtocol\ModelContextProtocol.csproj" />
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<ProjectReference Include="..\..\src\ModelContextProtocol.AspNetCore\ModelContextProtocol.AspNetCore.csproj" />
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</ItemGroup>
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</Project>

Diff for: ‎samples/AspNetCoreSseServer/McpEndpointRouteBuilderExtensions.cs

-62
This file was deleted.

Diff for: ‎samples/AspNetCoreSseServer/Program.cs

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@@ -1,10 +1,9 @@
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using AspNetCoreSseServer;
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using ModelContextProtocol.AspNetCore;
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var builder = WebApplication.CreateBuilder(args);
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builder.Services.AddMcpServer().WithToolsFromAssembly();
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var app = builder.Build();
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app.MapGet("/", () => "Hello World!");
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app.MapMcpSse();
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app.MapMcp();
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app.Run();

Diff for: ‎src/ModelContextProtocol.AspNetCore/McpEndpointRouteBuilderExtensions.cs

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@@ -0,0 +1,118 @@
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using Microsoft.AspNetCore.Builder;
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using Microsoft.AspNetCore.Http;
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using Microsoft.AspNetCore.Routing;
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using Microsoft.AspNetCore.WebUtilities;
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using Microsoft.Extensions.DependencyInjection;
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using Microsoft.Extensions.Logging;
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using Microsoft.Extensions.Options;
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using ModelContextProtocol.Protocol.Messages;
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using ModelContextProtocol.Protocol.Transport;
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using ModelContextProtocol.Server;
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using ModelContextProtocol.Utils.Json;
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using System.Collections.Concurrent;
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using System.Security.Cryptography;
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namespace ModelContextProtocol.AspNetCore;
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/// <summary>
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/// Extension methods for <see cref="IEndpointRouteBuilder"/> to add MCP endpoints.
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/// </summary>
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public static class McpEndpointRouteBuilderExtensions
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{
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/// <summary>
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/// Sets up endpoints for handling MCP HTTP Streaming transport.
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/// </summary>
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/// <param name="endpoints">The web application to attach MCP HTTP endpoints.</param>
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/// <param name="runSession">Provides an optional asynchronous callback for handling new MCP sessions.</param>
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/// <returns>Returns a builder for configuring additional endpoint conventions like authorization policies.</returns>
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public static IEndpointConventionBuilder MapMcp(this IEndpointRouteBuilder endpoints, Func<HttpContext, IMcpServer, CancellationToken, Task>? runSession = null)
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{
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ConcurrentDictionary<string, SseResponseStreamTransport> _sessions = new(StringComparer.Ordinal);
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var loggerFactory = endpoints.ServiceProvider.GetRequiredService<ILoggerFactory>();
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var mcpServerOptions = endpoints.ServiceProvider.GetRequiredService<IOptions<McpServerOptions>>();
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var routeGroup = endpoints.MapGroup("");
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routeGroup.MapGet("/sse", async context =>
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{
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var response = context.Response;
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var requestAborted = context.RequestAborted;
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response.Headers.ContentType = "text/event-stream";
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response.Headers.CacheControl = "no-cache";
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var sessionId = MakeNewSessionId();
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await using var transport = new SseResponseStreamTransport(response.Body, $"/message?sessionId={sessionId}");
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if (!_sessions.TryAdd(sessionId, transport))
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{
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throw new Exception($"Unreachable given good entropy! Session with ID '{sessionId}' has already been created.");
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}
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await using var server = McpServerFactory.Create(transport, mcpServerOptions.Value, loggerFactory, endpoints.ServiceProvider);
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try
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{
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var transportTask = transport.RunAsync(cancellationToken: requestAborted);
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runSession ??= RunSession;
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try
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{
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await runSession(context, server, requestAborted);
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}
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finally
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{
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await transport.DisposeAsync();
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await transportTask;
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}
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}
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catch (OperationCanceledException) when (requestAborted.IsCancellationRequested)
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{
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// RequestAborted always triggers when the client disconnects before a complete response body is written,
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// but this is how SSE connections are typically closed.
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}
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finally
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{
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_sessions.TryRemove(sessionId, out _);
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}
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});
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routeGroup.MapPost("/message", async context =>
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{
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if (!context.Request.Query.TryGetValue("sessionId", out var sessionId))
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{
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await Results.BadRequest("Missing sessionId query parameter.").ExecuteAsync(context);
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return;
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}
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if (!_sessions.TryGetValue(sessionId.ToString(), out var transport))
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{
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await Results.BadRequest($"Session {sessionId} not found.").ExecuteAsync(context);
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return;
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}
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var message = await context.Request.ReadFromJsonAsync<IJsonRpcMessage>(McpJsonUtilities.DefaultOptions, context.RequestAborted);
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if (message is null)
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{
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await Results.BadRequest("No message in request body.").ExecuteAsync(context);
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return;
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}
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await transport.OnMessageReceivedAsync(message, context.RequestAborted);
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context.Response.StatusCode = StatusCodes.Status202Accepted;
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await context.Response.WriteAsync("Accepted");
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});
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return routeGroup;
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}
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private static Task RunSession(HttpContext httpContext, IMcpServer session, CancellationToken requestAborted)
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=> session.RunAsync(requestAborted);
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private static string MakeNewSessionId()
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{
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// 128 bits
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Span<byte> buffer = stackalloc byte[16];
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RandomNumberGenerator.Fill(buffer);
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return WebEncoders.Base64UrlEncode(buffer);
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}
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}

Diff for: ‎src/ModelContextProtocol.AspNetCore/ModelContextProtocol.AspNetCore.csproj

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<Project Sdk="Microsoft.NET.Sdk">
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<PropertyGroup>
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<TargetFramework>net8.0</TargetFramework>
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<ImplicitUsings>enable</ImplicitUsings>
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<Nullable>enable</Nullable>
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<GenerateDocumentationFile>true</GenerateDocumentationFile>
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<IsPackable>true</IsPackable>
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<PackageId>ModelContextProtocol.AspNetCore</PackageId>
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<Description>ASP.NET Core extensions for the C# Model Context Protocol (MCP) SDK.</Description>
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<PackageReadmeFile>README.md</PackageReadmeFile>
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</PropertyGroup>
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<ItemGroup>
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<FrameworkReference Include="Microsoft.AspNetCore.App" />
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</ItemGroup>
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<ItemGroup>
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<None Include="README.md" pack="true" PackagePath="\" />
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</ItemGroup>
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<ItemGroup>
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<ProjectReference Include="..\ModelContextProtocol\ModelContextProtocol.csproj" />
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</ItemGroup>
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</Project>

Diff for: ‎src/ModelContextProtocol.AspNetCore/README.md

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# ASP.NET Core extensions for the MCP C# SDK
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[![NuGet preview version](https://img.shields.io/nuget/vpre/ModelContextProtocol.svg)](https://www.nuget.org/packages/ModelContextProtocol/absoluteLatest)
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5+
The official C# SDK for the [Model Context Protocol](https://modelcontextprotocol.io/), enabling .NET applications, services, and libraries to implement and interact with MCP clients and servers. Please visit our [API documentation](https://modelcontextprotocol.github.io/csharp-sdk/api/ModelContextProtocol.html) for more details on available functionality.
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> [!NOTE]
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> This project is in preview; breaking changes can be introduced without prior notice.
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## About MCP
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The Model Context Protocol (MCP) is an open protocol that standardizes how applications provide context to Large Language Models (LLMs). It enables secure integration between LLMs and various data sources and tools.
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For more information about MCP:
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- [Official Documentation](https://modelcontextprotocol.io/)
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- [Protocol Specification](https://spec.modelcontextprotocol.io/)
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- [GitHub Organization](https://github.com/modelcontextprotocol)
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## Installation
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To get started, install the package from NuGet
23+
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```
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dotnet new web
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dotnet add package ModelContextProtocol.AspNetcore --prerelease
27+
```
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## Getting Started
30+
31+
```csharp
32+
// Program.cs
33+
using ModelContextProtocol;
34+
using ModelContextProtocol.AspNetCore;
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var builder = WebApplication.CreateBuilder(args);
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builder.WebHost.ConfigureKestrel(options =>
38+
{
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options.ListenLocalhost(3001);
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});
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builder.Services.AddMcpServer().WithToolsFromAssembly();
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var app = builder.Build();
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app.MapMcp();
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app.Run();
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[McpServerToolType]
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public static class EchoTool
50+
{
51+
[McpServerTool, Description("Echoes the message back to the client.")]
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public static string Echo(string message) => $"hello {message}";
53+
}
54+
```

Diff for: ‎src/ModelContextProtocol/Client/McpClient.cs

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@@ -79,10 +79,9 @@ public async Task ConnectAsync(CancellationToken cancellationToken = default)
7979
{
8080
// Connect transport
8181
_sessionTransport = await _clientTransport.ConnectAsync(cancellationToken).ConfigureAwait(false);
82-
InitializeSession(_sessionTransport);
8382
// We don't want the ConnectAsync token to cancel the session after we've successfully connected.
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// The base class handles cleaning up the session in DisposeAsync without our help.
85-
StartSession(fullSessionCancellationToken: CancellationToken.None);
84+
StartSession(_sessionTransport, fullSessionCancellationToken: CancellationToken.None);
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// Perform initialization sequence
8887
using var initializationCts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
@@ -142,13 +141,14 @@ await SendMessageAsync(
142141
/// <inheritdoc/>
143142
public override async ValueTask DisposeUnsynchronizedAsync()
144143
{
145-
if (_connectCts is not null)
146-
{
147-
await _connectCts.CancelAsync().ConfigureAwait(false);
148-
}
149-
150144
try
151145
{
146+
if (_connectCts is not null)
147+
{
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await _connectCts.CancelAsync().ConfigureAwait(false);
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_connectCts.Dispose();
150+
}
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await base.DisposeUnsynchronizedAsync().ConfigureAwait(false);
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}
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finally
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{
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await _sessionTransport.DisposeAsync().ConfigureAwait(false);
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}
160-
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_connectCts?.Dispose();
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}
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}
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}

Diff for: ‎src/ModelContextProtocol/Configuration/McpServerBuilderExtensions.cs

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Throw.IfNull(builder);
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builder.Services.AddSingleton<ITransport, StdioServerTransport>();
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builder.Services.AddHostedService<McpServerSingleSessionHostedService>();
340+
builder.Services.AddHostedService<StdioMcpServerHostedService>();
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342342
builder.Services.AddSingleton(services =>
343343
{
@@ -350,18 +350,5 @@ public static IMcpServerBuilder WithStdioServerTransport(this IMcpServerBuilder
350350

351351
return builder;
352352
}
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/// <summary>
355-
/// Adds a server transport that uses SSE via a HttpListener for communication.
356-
/// </summary>
357-
/// <param name="builder">The builder instance.</param>
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public static IMcpServerBuilder WithHttpListenerSseServerTransport(this IMcpServerBuilder builder)
359-
{
360-
Throw.IfNull(builder);
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362-
builder.Services.AddSingleton<IServerTransport, HttpListenerSseServerTransport>();
363-
builder.Services.AddHostedService<McpServerMultiSessionHostedService>();
364-
return builder;
365-
}
366353
#endregion
367354
}

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